... All that makes me think that our tendency to exchange pain with other humans is something deeply human and needs to be accepted as it is. One thing we can do about it is to use it in a way that is nice for each of us. And I think the situation during an Aikido training provides quite a nice lab to learn about that. ...

Hm, in our Aikido (Our shihan are Endo Seishiro and Christian Tissier) we try to improve our technique to a level where it is very effective, but doesn't use pain to control or move the partner.